A compound having a hydrolyzable silyl group at its terminal is likely to undergo an intermolecular reaction or to form a chemical bond with the surface of a substrate. Therefore, such a compound is widely used as a surface treatment agent or a reactive adhesive. For example, by coating a substrate with a compound having a hydrolyzable silyl group introduced at a terminal of its molecule having a specific function, it is possible to bond the molecule having a specific function to the surface of the substrate.
As a method for introducing a hydrolyzable silyl group at a terminal, a method is preferably used wherein at a terminal of the molecule of a starting compound, a 2-propenyl group (—CH2CH═CH2, common name: allyl group) is introduced, and then, to the compound having the 2-propenyl group introduced, a hydrosilane compound is reacted for hydrosilylation. The hydrosilylation reaction may, for example, be carried out in the presence of a very small amount of a transition metal catalyst.
The method for introducing a 2-propenyl group at a terminal of the molecule of a starting compound, may, for example, be a method wherein a compound having a 3-halopropyl group at a terminal of its molecule is dehydrohalogenated to convert the terminal to a 2-propenyl group, or a method wherein a compound having a hydroxy group at a terminal of its molecule is reacted with an allyl halide to obtain an allyl ether compound having an allyloxy group (—O—CH2CH═CH2) at the terminal of its molecule.
However, the selectivity of the hydrosilylation reaction is not necessarily high depending on the type of the compound having a 2-propenyl group at a terminal of its molecule. For example, according to a hydrosilylation reaction of an allyl ether compound, the desired compound having a hydrolyzable silyl group at a terminal may be formed from 75 to 85 mol %, but at the same time, a by-product having a 1-propenyl group (—CH═CH—CH3) with the double bond moved to the inside would be formed from 15 to 25 mol % by a side reaction.
If the formation of such a by-product is high, the production cost for the desired compound tends to increase. Further, an additional process step of separating the compound and the by-product will be required. In general, in the case of a reaction of a compound with a low molecular weight, the boiling point of a desired compound becomes sufficiently higher than the boiling points of the starting material and by-product, and thus, they can easily be separated by distillation purification. However, if the starting material is a compound with a high molecular weight, the separation by distillation purification itself tends to be difficult, and it will be obliged to use the reaction mixture containing the desired compound and by-product, as it is, as a surface treatment agent, etc. In that case, if the by-product in the reaction mixture is substantial, the adhesion between the surface treatment agent and the substrate tends to be low, and the function as a surface treatment agent tends to be inadequate.
Further, for example, propenyl ether as a by-product having a 1-propenyl group, will, when reacted with water, form propionaldehyde which causes bad odor (see Patent Document 1).